Square



July 5, I K UYEDA ET AL SQUARE Filed Sept. 17, 1935 m2; Zro U eda/ (125M630 71 012541 Patented July 5, 1938 UNETED STATES PATENT OFFICE SQUARE Application September In Japan 0 1 Claim.

Our invention relates to a drafting implement, combined with a protractor.

The object of our invention is to obtain an isosceles, right angled triangle which is adapted to be used as a set square, protractor or ruler and in which one triangle is enough to measure any desired angles and to draw various lines in anydesired directions.

Various forms of implements of this type have been proposed but no type in general use at the present time can be used to measure over 90 or 180, whereas the triangle combined with a protractor according to our invention may be used to measure any desired angles, from 0 to 360.

According to our invention a right, angled isosceles triangle consisting of celluloid, bakelite or other transparent material is formed with a quadrantal opening whose curved edge is radially graduated to form a protractor and on the opposite side of this opening auxiliary dividing lines are drawn radially from the center of the protractor.

Our invention will be better understood from the following description when considered in connection with accompanying drawing and its scope will be pointed out in the claim.

In the drawing: I

Figure 1 is a plan View of one embodiment of our invention.

Figure 2 is a plan view of another embodiment of our invention, and

Figures 3, 4 and 5 illustrate examples of the use of the implement.

Referring to the numerals on the drawing, I is an isosceles triangle made of celluloid, bakelite or other transparent material in which is formed a quadrantal opening 2, as in Figure 1. Both side edges 3 of the opening 2 are parallel to the equal sides of the triangle 1 and a scale 4 is marked on the curved edge of the opening 2, said scale beng divided radially from a corner point 0 of the side edges 3 and on the equal sides of the triangle l auxiliary dividing lines 5 are drawn radially from the focal point 0 so that angles 17, 1935, Serial No. 40,972 ctober 3, 1934 from 0 to 270 around the focal point 0 may be indicated by these auxiliary lines 5. In this triangle the inclined edge 6 may be graduated to be adapted for use as a ruler or straight edge.

In the modification shown in Figure 2, the triangle is provided with a plurality of curved slots 1, the curvature of said slots gradually decreasing from the point 0 to the hypothenuse of the triangle, each curved edge of these slots being marked with a scale ranging from 0 to 90.

The implement according to our invention is constructed as above described and can be used to measure any desired angle from 0 to 360; for example, 156 from a line OY may be measured in such a manner that the line OY registers with the definite auxiliary line 0' and a line OX at the graduation 66 on the scale 4 is drawn, thus the desired angle XOY is obtained.

To measure 30 at the point 0' from a line AB as shown in Figure 3, the line AB registers on the third line 5 intersecting a line 0C drawn by the side edge of the triangle I; thus the desired angle BOC is obtained.

In drawing plural lines at different angles, for example 3, 6, 7, 12, and 22, said lines are drawn radially from the focal point 0 of the opening 2. An angle of 3 is formed by placing the device so that line AB passes through point 0 and the 3 graduation of scale 4 and utilizing edge 3 to draw line OC. Other angles are correspondingly formed.

We claim:

A drafting instrument consisting of an isosceles triangle of transparent material provided with a segmental opening having straight edges which are radial to a definite focal point and having a curved arcuate edge with graduations thereon representing degrees of a circle, the sides of the triangle being provided with protracting lines registering with the lines on the curved edge of the segmental opening and concentrating at the same focal point.

KATSUJIRO UYEDA. ITSUO WOOGA. 

